Anisotropic Electron-Phonon Coupling and Dynamical Nesting on the Graphene Sheets in Superconducting CaC6 using Angle-Resolved Photoemission Spectroscopy

作者:Valla T*; Camacho J; Pan Z H; Fedorov A V; Walters A C; Howard C A; Ellerby M
来源:Physical Review Letters, 2009, 102(10): 107007.
DOI:10.1103/PhysRevLett.102.107007

摘要

We present the first angle-resolved photoemission studies of electronic structure in CaC6, a superconducting graphite intercalation compound with T-c=11.6 K. We find that, contrary to theoretical models, the electron-phonon coupling on the graphene-derived Fermi sheets with high-frequency graphene-derived phonons is surprisingly strong and anisotropic. The shape of the Fermi surface is found to favor a dynamical intervalley nesting via exchange of high-frequency phonons. Our results suggest that graphene sheets play a crucial role in superconductivity in graphite intercalation compounds.

  • 出版日期2009-3-13